Problem: $ { \left[\begin{array}{rrr}{3} & {-1} & {1} \\ {-1} & {2} & {1}\end{array}\right]-\left[\begin{array}{rrr}{0} & {1} & {0} \\ {-2} & {2} & {-2}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rrr}{3}-{0} & {-1}-{1} & {1}-{0} \\ {-1}-{-2} & {2}-{2} & {1}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{3} & {-2} & {1} \\ {1} & {0} & {3}\end{array}\right]}$